Increasing the discharge arc diffuseness in mercury-free discharge lamps

Abstract

A mercury-free gas discharge lamp suitable in particular for motor vehicles has an enhanced discharge arc diffuseness. The lamp according includes an inner vessel and/or outer bulb with a structured arrangement or pattern such that the discharge arc diffuseness of the lamp is increased, such as by 0.01 mm to 1.5 mm.

1. A mercury-free gas discharge lamp comprising:
 an inner vessel including electrodes for providing a discharge arc; and 
 an outer bulb, wherein a surface of at least one of the inner vessel and the outer bulb is altered to form a pattern configured to increase a diffuseness of the discharge arc, wherein the pattern includes structured arrangements formed on the surface, the structured arrangements physically overlapping over each so that a first structured arrangement is in physical contact with a second structured arrangement. 
 
   
   
     2. The mercury-free gas discharge lamp as claimed in  claim 1 , wherein the pattern is configured to increase the diffuseness of the discharge arc of the mercury-free gas discharge lamp by 0.01 mm up to 1.5 mm in comparison with a corresponding gas discharge lamp without the pattern. 
   
   
     3. The mercury-free gas discharge lamp as claimed in  claim 1 , wherein the pattern is configured to reduce the discharge arc curvature of the mercury-free gas discharge lamp by 0.01 mm up to 0.5 mm in comparison with a corresponding gas discharge lamp without the pattern. 
   
   
     4. The mercury-free gas discharge lamp as claimed in  claim 1 , wherein the mercury-free gas discharge lamp is at least one of a mercury-free high-pressure gas discharge lamp, and a mercury-free xenon high-pressure gas discharge lamp. 
   
   
     5. The mercury-free gas discharge lamp as claimed in  claim 1 , wherein light losses of the mercury-free gas discharge lamp as compared with a gas discharge lamp without the pattern amount to ≦90 lumens and ≧5 lumens. 
   
   
     6. The mercury-free gas discharge lamp as claimed in  claim 1 , wherein the at least one of the inner vessel and the outer bulb is made of at least one of glass and ceramic materials. 
   
   
     7. The mercury-free gas discharge lamp as claimed in  claim 1 , wherein the at least one of the inner vessel and the outer bulb has the pattern at least one of on its outer surface facing away from the discharge arc, on its outer surface facing the discharge arc, and within the inner vessel or bulb material. 
   
   
     8. The mercury-free gas discharge lamp as claimed in  claim 1 , wherein the pattern is formed by at least one of a laser treatment, sandblasting, surface etching, surface slitting and roughening, and is optionally finished by fire polishing. 
   
   
     9. The mercury-free gas discharge lamp as claimed in  claim 1 , wherein the pattern covers a surface area of 2 mm 2  to 12 mm 2 , said surface area being arranged over a brightest spot in the discharge arc. 
   
   
     10. The mercury-free gas discharge lamp as claimed in  claim 1 , wherein the mercury-free gas discharge lamp is configured for motor vehicles. 
   
   
     11. The mercury-free gas discharge lamp of  claim 1 , wherein the pattern is further configured to provide an optical impression when viewed from an exterior of the mercury-free gas discharge lamp, the optical impression showing a change in a viewed position of a brightest spot of the discharge arc despite lack of an actual change of an actual position of the brightest spot within the mercury-free gas discharge lamp. 
   
   
     12. The mercury-free gas discharge lamp of  claim 1 , wherein the pattern is further configured to not change an actual position of a brightest spot of the discharge arc and yet provide an optical impression showing a perceived change in a perceived position of a brightest spot when viewed from an exterior of the mercury-free gas discharge lamp. 
   
   
     13. The mercury-free gas discharge lamp of  claim 1 , wherein the pattern includes at least one of lines, dots, circles, rectangles, and polygons. 
   
   
     14. The mercury-free gas discharge lamp of  claim 13 , wherein the lines includes at least one of straight, curved, wavy, and spiraling lines. 
   
   
     15. The mercury-free gas discharge lamp of  claim 13 , wherein the structured arrangements are at least one of same and different sizes, and are partly or fully planar in shape. 
   
   
     16. The mercury-free gas discharge lamp of  claim 1 , wherein the structured arrangements are at least one of partly and fully planar. 
   
   
     17. A discharge lamp comprising:
 an inner vessel including electrodes for providing a discharge arc; and 
 an outer bulb, wherein at least one of the inner vessel and the outer bulb is altered to form a pattern configured to increase a diffuseness of the discharge arc, wherein the pattern includes structured arrangements that are physically overlapping over each other so that a first structured arrangement is in physical contact with a second structured arrangement. 
 
   
   
     18. The discharge lamp of  claim 17 , wherein the pattern is further configured to provide an optical impression when viewed from an exterior of the discharge lamp, the optical impression showing a change in a viewed position of a brightest spot of the discharge arc despite lack of an actual change of an actual position of the brightest spot within gas discharge lamp. 
   
   
     19. The discharge lamp of  claim 17 , wherein the pattern is further configured to not change an actual position of a brightest spot of the discharge arc and yet provide an optical impression showing a perceived change in a perceived position of a brightest spot when viewed from an exterior of the discharge lamp. 
   
   
     20. The discharge lamp of  claim 1 , wherein the pattern includes homogeneously overlapping rings arranged in at least one of row and columns formed by at least one of a laser treatment, sandblasting, surface etching, surface slitting and roughening. 
   
   
     21. The discharge lamp of  claim 17 , wherein the pattern includes homogeneously overlapping rings arranged in at least one of row and columns formed by at least one of a laser treatment, sandblasting, surface etching, surface slitting and roughening.